This invention relates to battery powered security monitoring systems for gaming machines such as slot machines or video poker machines. More particularly, the present invention relates to secure monitoring of gaming machine access ports.
There are wide variety of associated devices that can comprise a gaming machine such as a slot machine or video poker machine. Some examples of these devices are lights, coupon dispensers, card readers, bill validators, coin acceptors, coin hoppers, display panels, key pads, and gaming controllers. Many of these devices are built into the gaming machine while some are grouped into separate units such as top boxes which may be placed on top of the machine.
Some gaming machine devices are considered more critical to the gaming machine operations than others. In particular, devices that control the input and output of money from the gaming machine are generally considered critical devices. The gaming controller, which controls the features of the game played on the gaming machine including the pay-out of a particular game as well as the gaming devices which output game pay-outs, is one of the most critical gaming devices, if not the most critical device. Specific examples of other critical devices include card readers, bill validators, ticket coupon readers, and coin acceptors which control the input of money into the gaming machine and note stackers, token dispensers, drop boxes and ticket/coupon dispensers which control the output of money from the gaming machine.
Access to a particular gaming machine device depends on the type of device. Input devices such as bill validators, coin acceptors, and card readers or output devices such as coupon dispensers or token dispensers are directly accessible. These devices have at least one access mechanism on the outside of the gaming machine so that the gaming machine may either accept money or indicia of credits from players desiring to play the game or pay-out money to a player playing a game. However, access to the mechanisms controlling the operation of these devices is usually behind one or more doors provided on the gaming machine exterior. The gaming controller and the money storage devices such as bill stackers and drop boxes are less accessible. These devices are usually only accessible after opening one or more doors or other barriers which limit access to these critical devices.
The doors which allow access to the critical devices are often secured with keyed locks. For security, when any of these doors are opened, the gaming machine must stop normal game play operation and switch to an attention state. Thus, it is necessary to detect whether a door is open or closed via an electronic means so that the operating software utilized by the gaming controller can take appropriate action.
Another access mechanism to gaming devices including bill validators, coin acceptors, token dispensers, gaming controllers, and coupon dispensers is through wires which accept and transmit signals which control the operation of the device. Typically, during the operation of the gaming machine, many of the associated gaming devices are controlled in some manner by the gaming controller located within the gaming machine. The control of a gaming device is enabled by the wires which connect a gaming device to the gaming controller. For example, when a player is playing a game and receives a pay-out during the course of a game, the gaming controller may send out a signal to a coupon dispenser, located in some of other part of the gaming machine away from the gaming controller, instructing the coupon dispenser to dispense a coupon representing the pay-out. Thus, access may be gained to a gaming device, via the wires connected to the gaming device.
A common mode of theft for gaming machines involves accessing the devices which control the input and output of money to the gaming machine through some access mechanism and manipulating the devices in some manner to obtain an illegal pay-out. For example, one type of theft might involve simply taking money from a drop box while a gaming machine is being accessed for maintenance. Another type of theft might involve illegally gaining access to the gaming controller and reprogramming the gaming controller to pay-out an illegal jack pot. Another type of theft might involve compromising the wires to a coupon dispenser and sending a signal instructing it to dispense coupons with some monetary value.
One method for preventing theft is installing a security system which monitors the various access mechanisms of a gaming machine. Typically, security devices of this type monitor access to the various entry ports within the gaming machine as well as the wires to some gaming devices. The security system monitors access to the entry port by sending out signals to sensors able to detect whether access to the entry port has occurred. Usually, the entry port contains a sensor device that forms some type of closed circuit when the entry port is closed and an open circuit when the entry port is open. When an entry port is opened, some information regarding this event is stored by the security monitoring system. For example, the security monitoring system might store information regarding whether a particular entry port was accessed during a particular period of time. This information can be used to determine when a theft has occurred or when tampering with the gaming machine has occurred.
Security monitoring of access to the gaming machine is usually implemented in some manner by the gaming controller during normal operations of the gaming machine in conjunction with some security monitoring hardware independent of the gaming controller. The security monitoring by the gaming controller is implemented while the gaming machine is receiving power from an external power source such as AC power from a power outlet. In the event the gaming machine is receiving no external power such as during a power failure or when the gaming machine is being stored or shipped, security monitoring of the gaming machine is carried out only by the independent security monitoring hardware powered by an internal power source within the gaming machine such as battery.
Since the door access security monitoring system is utilized to detect theft or tampering with gaming machine, some individuals desiring to steal or tamper with the gaming machine have developed methods for thwarting such devices. One disadvantage of current access mechanism security monitoring systems is that approaches to defeating the systems have been developed by obtaining a schematic of the circuitry hardware used in the system and developing techniques for preventing an access event from being recorded when an access has occurred. For example, connections between certain gates on the circuit could be rewired to prevent the circuit from detecting an access event. Accordingly, it would be desirable to provide a door access security monitoring system which contains custom circuitry which prevents this type of tampering.
Another disadvantage of current access mechanism security monitoring systems is that the approaches to tampering with the gaming machine between monitoring intervals by the system have been developed. For example, it is possible to open a door on gaming machine between monitoring intervals and then send out a false signal such that the security monitoring system never records that the gaming machine door has been opened. According, it would be desirable to provide an access security mechanism security monitoring system which prevents this type of tampering from occurring.
This invention addresses the needs described above by providing a security system that monitors validation signals detected by a sensor at least twice during each oscillation of the validation signal. This technique may be applied both while the main power to the gaming machine is on and while a backup power source (e.g., a battery) is on. Preferably, the security system of this invention employs a custom integrated circuit (e.g., an end-user programmed complex programmable logic device) to perform some the security functions such as supplying the validation signal to the sensor and comparing a sensor output signal to the validation signal to determine whether access to a gaming machine device has occurred.
One aspect of the present invention pertains to a gaming machine, which may be characterized by the following features: (a) a plurality of gaming devices coupled to the gaming machine (b) an access mechanism allowing access to one or more gaming devices of said gaming machine; and (c) access monitoring circuitry. The access monitoring circuitry preferably includes (i) a sensor including a signal emitter and a signal detector indicating when the access mechanism has been actuated in a manner in allowing access to one or more of the gaming devices; (ii) a source circuit providing an oscillating validation signal controlling operation of the sensor""s signal emitter; and (iii) a detection circuit for monitoring the output of the sensor""s signal detector in a manner sampling the output at least twice within a single oscillation.
Various sensors may be employed with this invention. Examples include optical sensors, magnetic sensors, and mechanical sensors. Likewise, various access mechanisms may be employed. Examples include locks, wires, retaining latches and device receptors. In a typical scenario, the access mechanism is provided on a door such as the main door of the gaming machine, a bill stacker door, a CPU security door, a belly door, a drop door and a coupon dispenser door. Depending upon the type of access mechanism employed, the access mechanism may be actuated by opening a door, unengaging a lock, accessing a signal path on wire, opening a retaining latch, or emptying a device receptor. In a specific embodiment, the detection circuit can monitor the output of at least 7 sensors simultaneously.
To obtain optimal security, the detection circuit should sample the output of the sensor""s detector at times when the output magnitude is expected to be at different levels. In other words, if the output signal is expected to oscillate between high and low states (on and off states in a digital system), then that signal should be sampled while the signal is expected to be high and again while it is expected to be low. To conserve power, the high portion of the signal may be of much shorter duration than the low portion of the signal. Thus, it can be very important to time the sampling so that both the expected high and low portions of the output signal are sampled. In a preferred embodiment, the validation signal and a sample rate of the detector""s output by the detection circuit are in synchronization and are at least 30 Hz.
In a specific embodiment, the access monitoring circuitry includes an inverter arranged to invert signals emitted by the source circuitry. Thus, the detection circuitry must expect to receive an inverted signal. If the signal is not inverted, access may have occurred. The access monitoring circuitry may require an amplifier arranged to amplify signals emitted by the source circuitry.
As mentioned, some or all of the security circuitry may be provided on an integrated circuit such as a custom integrated circuit. Examples of such custom ICs include programmable logic devices, field programmable gate arrays, and application specific integrated circuits. Preferably, the source circuit and the detection circuit are provided on a single integrated circuit.
As mentioned, the invention preferably operates while the gaming machine""s main power supply is not operable. Thus, the gamine machine may include a battery that provides power to the source circuit and to the detection the sensor. Preferably, the battery can power the entire security system including the integrated circuit.
Another aspect of the invention provides a custom integrated circuit for use in detecting access via one or more access mechanisms of a gaming machine. As mentioned, examples of suitable custom integrated circuits include programmable logic devices, field programmable gate arrays, and application specific integrated circuits. In this embodiment, each of the access mechanisms has at least one associated sensor, as described above. The custom integrated circuit may be characterized by the following elements: (a) a source circuit providing an oscillating validation signal for controlling operation of a sensor""s signal emitter; (b) a detection circuit for monitoring an output signal of the sensor""s signal detector by sampling the output signal at least twice within a single oscillation of the validation signal; (c) comparison circuitry for comparing the values of the output signal sample and the validation signal at particular times; and (d) a storage region for storing data indicating when access has been detected by the comparison circuitry.
The integrated circuit may also include a power connection allowing a battery to be coupled to the custom integrated circuit such that the battery powers the source circuit, the detection circuit, and the comparison circuitry. Further, the integrated circuit may include a connection to a master clock that provides a timing signal with a frequency of 30 Hz or greater. Still further, the integrated circuit may include a connection allowing a device external to the custom integrated circuit to read the contents of the storage region.
In a preferred embodiment, the storage region is provided as one or more registers. One of these may be dedicated to storing access indicators for separate sensors on the gaming machine. In a specific embodiment, the storage region can provide information on at least 7 sensors. Another register may store a random number which is overwritten when access to special devices (e.g., the CPU) has occurred. A power status register may be provided for storing signals on the operational status of one or more power sources. Examples of such power sources include a main power supply, a battery for powering the sensor, and a battery for powering the storage region.
Yet another aspect of this invention pertains to a method of monitoring an access mechanism that allows access to one or more gaming devices within a gaming machine. The method employs a sensor that provides an output signal indicating whether the access mechanism has allowed access. The method may be characterized by the following sequence: (a) sending an oscillating validation signal to the sensor, the validation signal controlling generation of an emitter signal at the sensor; (b) detecting the output signal from a signal detector of the sensor; (c) comparing the value of the validation signal and the value of the output signal at least twice during a single oscillation; and (d) indicating access to the gaming machine when compared values of the validation signal and the output signal show that access to the gaming machine feature has occurred.
Preferably, the method also allows the security system to determine whether it is on main power or backup power. Different security protocols may be employed depending on whether main or backup power is used. Preferably, a backup power protocol drains energy at a low rate. In a specific embodiment, the method requires storing a power signal indicating whether the gaming machine is using normal power or backup power.
The method may indicate access by various mechanisms. For example, it may store a signal indicating that access has occurred through a specific access mechanism. The signal is stored in a non-volatile memory such as a register on a custom integrated circuit, as discussed above. For critical access mechanisms, the method may involve (i) storing an identical random string of numbers to two non-volatile memory locations within the gaming machine when main power is on to the gaming machine; and (ii) clearing the random number located within one of the non-volatile memory locations when access to one or more specified access mechanisms has occurred while main power is off.
Note that the method may also determine when main power to the gaming machine is off and then power the security system (including the sensor) with battery power. To allow the gaming machine to recognize that it is in a backup power state, the method may store a power signal indicating that primary power to the gaming machine is off. The method may further require (i)monitoring a voltage level in the battery; and (ii) clearing a battery status indicator stored in a non-volatile memory located on the custom integrated circuit when the battery voltage is below a defined level.